Final answer:
Birds such as ducks, geese, and swans are able to sit on water due to a combination of factors, including a special oil coating on their feathers, air sacs that provide buoyancy, and their body structure.
Step-by-step explanation:
Birds such as ducks, geese, and swans are able to sit on water due to several factors:
- Water does not wet their feathers due to a special coating of oil present on their feathers. This oil repels water, allowing them to remain dry and float on the surface.
- Birds have air sacs within their bodies that help with buoyancy. These air sacs are filled with air, which makes their overall density less than that of water, allowing them to float on the surface.
- The shape and structure of their bodies, such as having large and broad feet or webbed feet, also help distribute their weight and increase surface area, contributing to their ability to sit on water.